British PM says `highly likely` Russia behind spy attack

In a dramatic escalation of diplomatic tensions over the attack on Sergei Skripal and his daughter on March 4, May said the nerve agent that poisoned them was a military-grade type developed by Russia. She told parliament that Moscow had previously used this group of nerve agents known as Novichok, had a history of state-sponsored assassinations and viewed defectors such as Skripal as legitimate targets. "The government has concluded that it is highly likely that Russia was responsible for the act against Sergei and Yulia Skripal," she told the House of Commons.

In its first comments on the case Monday, the White House offered its support to Britain, calling the attack "an outrage". But press secretary Sarah Sanders stopped short of referencing any possible Russian involvement. "The attack was reckless, indiscriminate and irresponsible," she said.

Meanwhile French President Emmanuel Macron "offered his solidarity with the UK" in a phone call with May, Downing Street said. "They discussed the wide pattern of aggressive Russian behaviour and agreed that it would be important to continue to act in concert with allies to address it," it added.